Improvement in pumps



v UNITED STATES GEORGE MARSHALL,

PATENT OFFICE.

0E NEw YORK, N. Y.

IMPRQVEMENT IN PUMPS.

` pump constructed according to my invention.

Fig. 2 is a horizontal section on the line :v

Similar letters of reference indicate corresponding paris in both figures.

This invention consists in the employment of a single-disk valve in a hollow piston attached to the lower end of a central dischargepipe, which passes through the upper end of the pumpcylinder and serves as the rod for workin g the piston, whereby I obtain a double-acting pump of very simple construction.

To enable others skilled in the art to make and use my invention, I will proceed to de scribe it with reference to the drawings.

A is the upright cylinder of the pump, cast with an upright side pipe, A', which always communicates with the cylinder by an opening, a, close to the Itop thereof. This cylinder is placed on the top of theinlet-chamber B of the pump, with which the suction-pipe is connected at b. This inlet chamber communicates with the cylinder by an inlet-vale, c, and with the side pipe by an inlet-valve, d. These valves may be of any suitable kind.

C is the hollow piston, fitted to the cylinder A, and having openings or ports e e in the top and similar openings or ports, ff, in tle bottom.

D is the central discharge-pipe, to the lower end of Whichthepiston is attached, and which is always in free communication with the interior ofthe piston. This pipe passes through a stuffing-box, g, in the cylinder-cover E in such manner that by a suitable connection outside of the said cover it will be made to serve as the piston-rod for working the piston.

F is the sin gle-disk valve contained within the hollow piston C, and serving as the discharge-valve of the pump in both the upward and downward stroke of the piston. This valve consists simply of a plate of metal or interior surfaces of the top and bottom of the cylinder being faced to form seats for it. The said valve has a central opening, h, of a size not less than the internal caliber of the central discharge-pipe, D, so that when it is in contact with the upper surface of the interior of the piston it'does not obstruct the passage of water into the said pipe.

The operation is as follows: In the upward stroke of the piston the valve Fis at the bottom of the piston, closing the ports ff and leaving e e open, the valve c is open, and the valve d closed. The water enters the cylinder by the valve c, and follows the piston upward, while the water with which the cylinder has been previously filled above the piston is forced on through the ports e e, the interior of the piston and the central discharge-pipe.

In the downward stroke of the piston the valve c is closed, the valve Fis forced against the top of the piston, closing the ports e e and leaving uf f open, and the valve d is closed. The water enters the cylinder through the side pipe, A', and opening a, and follows the piston downward, while the water with which the cylinder has been previously filled below the piston is forced out through the ports ff,

the interior of the piston, and the central disnea th it and a valve, c, leading into it beneath the piston, substantially as described.

GEORGE MARSHALL.

Witnesses HENRY T. BROWN, GEO. W. REED. 

